I develop some different products using the microcontroller PIC32MX460F512L. All the products are affected by problems with the ESD discharge test EN 61000-4-2.When arrive a discharge, the microcontroller perform a reset. It happen also using a coupling plane near to the microcontroller, without allow to the discharge to direct arrive to the board.On the board are present a Transil on the 3V3 and all the requested ceramic capacitor.It's not easy to solve the problem because there isn't a particular problematic pin, the ESD arrive only at the external test plane.

What is conmected to your MCLR pin (even if it is disabled)Are all your pins either tied high/low, or set to output?Do you have a bypass capacitor mounted as close as possible to every pair of power pins?

Latest test project, an LED matrix display made from one reel of addressable LEDs. here